This paper provides a critical analysis of modern slavery (MS) policy, legislation and discourse in the United Kingdom. Challenging the suggestion that recent attempts to dilute protections and guarantees in the original MS framework represent a fundamental shift from a more humanitarian to a more punitive orientation, it argues that these two moments ought to be understood as products of a single, underlying articulation, the ‘punitive–humanitarian complex’. We first explore the context and discourse of the MS agenda, exposing an ambivalence within its core tenets, primarily manifested through the dichotomy between victims (slaves) and offenders (slavers). The paper then examines how the punitive–humanitarian complex engenders moral and affective economies and reflects on how it reveals the vulnerability of contemporary state power.